The present invention relates to a coated cemented carbide cutting tool insert. More specifically the invention relates to PVD coated cemented carbide cutting tool inserts for semifinishing or finishing metal cutting operations.
High performance cutting tools must possess high wear resistance, high toughness properties and good resistance to plastic deformation. This is particularly valid when the cutting operation is carried out at high cutting speeds and/or at high feed rates when large amount of heat is generated.
Cemented carbide grades for metal machining applications generally contain WC, γ-phase, which is a solid solution of generally TiC, NbC, TaC and WC, and a binder phase, generally Co and/or Ni. WC—Co cemented carbides having a fine grain size less than about 1 μm are produced through the incorporation of grain growth inhibitors such as V, Cr, Ti, Ta and combinations thereof in the initial powder blend. Typical inhibitor additions are from about 0.5 to about 5 wt-% of the binder phase.